Augmentation mammoplasty, that is, surgical augmentation of the breasts, is a common cosmetic surgical procedure that has been performed for many years. This procedure usually entails making a surgical incision to create a pocket in the breast and then inserting a mammary prosthesis, generally shaped similar to the human breast, into the pocket.
Mammary prostheses are well known in the art and generally take several forms. There are single unitary mammary prostheses which comprise a shell of physiologically inert material, such as silicone rubber or the like which are filled with a silicone gel or a saline solution and then sealed. Inflatable mammary prostheses are also available and generally include a hollow shell of physiologically inert material such as silicone rubber which is filled with a saline solution during surgery to achieve the appropriate prosthesis and breast size. In addition to the single shell inflatable mammary prosthesis, an inflatable bilumen or double shell mammary prosthesis is also available. The inflatable bilumen mammary prosthesis generally includes an inner gel implant filled within silicone gel and then sealed. The inner gel implant is disposed within a partially fluid filled, inflatable shell that is further filled through a valve with a saline solution during surgery to achieve the desired breast augmentation.
Both the single shell inflatable mammary prosthesis and the inflatable bilumen mammary prosthesis advantageously permit the size and, in particular, the projection or height of the mammary prosthesis to be varied by altering the amount of fluid admitted to the prosthesis. However, admitting additional fluid into the prosthesis to increase the mammary prosthesis projection also results in an increase in the mammary prosthesis base diameter, which may be very undesirable. Increasing the mammary prosthesis base dimension once the prosthesis has been inserted may cause tearing of the tissue and possible bleeding. While the projection of the single shell inflatable mammary prosthesis and the inflatable bilumen mammary prosthesis can be varied slightly by the addition of fluid to the prosthesis without severely altering the base dimension of the prosthesis, to obtain a significant increase in the prosthesis projection, it is necessary to employ a prosthesis having a larger molded shell.